The function of Atlantic salmon (Salmo salar L.) antibodies under extremes of pH and osmolarity

The ability of anti-MBP Atlantic salmon antibodies to bind to MBP was investigated using ELISA under a range of pHs (3–10) and osmolarities (100–1000 mOsml−1) to determine the optimum binding conditions required for Atlantic salmon antibodies. The pH optimum was between pH 7–8 with pH 7·4 giving the highest level of antibody binding. However, the decrease in optical density was in excess of 60% at pHs 6·0 and 9·0 and in excess of 99% at pHs of 3·0 and 10·0. The optimum osmolarity required for antibody binding was in the range 100–400 mOsml−1 with 330 mOsml−1 giving the highest level of antibody binding. Above 400 mOsml−1 there was a rapid decrease in antibody binding with the OD dropping by over 50% at all dilutions. This decrease was maintained at all osmolarities over 400 mOsml−1